title: The PGPR strain Phyllobacterium brassicacearum STM196 induces a reproductive delay and physiological changes that result in improved drought tolerance in Arabidopsis.
abstract: Understanding how biotic interactions can improve plant tolerance to drought is a challenging prospect for agronomy and ecology. Plant growth-promoting rhizobacteria (PGPR) are promising candidates but the phenotypic changes induced by PGPR under drought remain to be elucidated. We investigated the effects of Phyllobacterium brassicacearum STM196 strain, a PGPR isolated from the rhizosphere of oilseed rape, on two accessions of Arabidopsis thaliana with contrasting flowering time. We measured multiple morphophysiological traits related to plant growth and development in order to quantify the added value of the bacteria to drought-response strategies of Arabidopsis in soil conditions. A delay in reproductive development induced by the bacteria resulted in a gain of biomass that was independent of the accession and the watering regime. Coordinated changes in transpiration, ABA content, photosynthesis and development resulted in higher water-use efficiency and a better tolerance to drought of inoculated plants. Our findings give new insights into the ecophysiological bases by which PGPR can confer stress tolerance to plants. Rhizobacteria-induced delay in flowering time could represent a valuable strategy for increasing biomass yield, whereas rhizobacteria-induced improvement of water use is of particular interest in multiple scenarios of water availability.
authors.affiliation: Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), UMR759, INRA-SupAgro, Montpellier, F-34060, France.|Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR113, Université Montpellier 2-IRD-CIRAD-INRA-SupAgro, F-34095, Montpellier, France.
authors.forename: Justine
authors.initials: J
authors.lastname: Bresson
authors.affiliation: Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR113, Université Montpellier 2-IRD-CIRAD-INRA-SupAgro, F-34095, Montpellier, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Varoquaux
authors.affiliation: Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), UMR759, INRA-SupAgro, Montpellier, F-34060, France.|Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR113, Université Montpellier 2-IRD-CIRAD-INRA-SupAgro, F-34095, Montpellier, France.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Bontpart
authors.affiliation: Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR113, Université Montpellier 2-IRD-CIRAD-INRA-SupAgro, F-34095, Montpellier, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Touraine
authors.affiliation: Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), UMR759, INRA-SupAgro, Montpellier, F-34060, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Vile
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000382:microbiology* / Q000502:physiology; D018533:Biomass; D002244:Carbon / Q000378:metabolism*; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D010641:Phenotype; D010788:Photosynthesis / Q000502:physiology; D059127:Phyllobacteriaceae / Q000502:physiology*; D018515:Plant Leaves / Q000254:growth & development / Q000382:microbiology / Q000502:physiology; D018520:Plant Shoots / Q000254:growth & development / Q000382:microbiology / Q000502:physiology; D054046:Plant Stomata / Q000254:growth & development / Q000382:microbiology / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology*; D012098:Reproduction; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water; D002244:Carbon
keywords: Arabidopsis thaliana; Phyllobacterium brassicacearum STM196; drought tolerance; flowering phenology; plant growth-promoting rhizobacteria (PGPR); water-use efficiency